In a study reported in the Journal of Clinical Oncology, Jackson et al found that the common practice of omitting androgen-deprivation therapy (ADT) from treatment with external-beam radiotherapy (EBRT) plus a brachytherapy boost (BT) may be associated with poorer overall survival in men with intermediate- or high-risk localized prostate cancer.
As stated by the investigators, despite lack of evidence supporting omission of ADT in this setting, available data indicate that 30% to 40% of intermediate- and high-risk patients receiving EBRT and BT do not receive ADT.
“Our findings suggest that current practice patterns of omitting ADT with EBRT plus BT may result in inferior overall survival compared with EBRT plus ADT in men with intermediate- and high-risk prostate cancer. ADT for these men should remain a critical component of treatment regardless of radiotherapy delivery method until randomized evidence demonstrates otherwise.”— Jackson et al
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Study Details
The study involved meta-analyses of data from six randomized trials that compared EBRT vs EBRT plus ADT (n = 4,663) and three that compared EBRT vs EBRT (with or without ADT) vs EBRT plus BT (n = 718). All trials included reporting of overall survival outcomes. Among all patients in the nine trials, 84% had intermediate- or high-risk disease. A standard meta-analysis was performed to assess the effects of the addition of ADT to EBRT and the addition of BT to EBRT, and a network meta-analysis was performed to compare predicted outcomes of a randomized trial comparing EBRT plus ADT vs EBRT plus BT.
Key Findings
In the standard meta-analysis, the addition of ADT to EBRT significantly improved overall survival (hazard ratio [HR] = 0.71, 95% confidence interval [CI] = 0.62–0.81). No significant improvement was found for the addition of BT to EBRT (HR = 1.03, 95% CI = 0.78–1.36).
In the network meta-analysis, EBRT plus ADT was associated with significantly improved overall survival vs EBRT plus BT (HR = 0.68, 95% CI = 0.52–0.89).
Bayesian modeling indicated a probability of 88% that EBRT plus ADT would result in superior overall survival vs EBRT plus BT and a probability of 87% that EBRT plus ADT would result in superior overall survival compared with both EBRT alone and EBRT plus BT.
The investigators concluded, “Our findings suggest that current practice patterns of omitting ADT with EBRT plus BT may result in inferior overall survival compared with EBRT plus ADT in men with intermediate- and high-risk prostate cancer. ADT for these men should remain a critical component of treatment regardless of radiotherapy delivery method until randomized evidence demonstrates otherwise.”
William C. Jackson, MD, of the Department of Radiation Oncology, University of Michigan, Ann Arbor, is the corresponding author for the Journal of Clinical Oncology article.
Disclosure: The study was supported the National Institutes of Health, Prostate Cancer Foundation, and philanthropic gifts from patients. For full disclosures of the study authors, visit ascopubs.org.
